Co-infection with Nippostrongylus brasiliensis does not impair host resistance during chronic Mycobacterium tuberculosis infection: a protective role for granulomas? (P3094)

• Published in: The Journal of immunology (1950) 2013-05, Vol.190 (1_Supplement), p.187-187.18
• Main Authors: Rafi, Wasiulla, Potian, Julius, Bhatt, Kamlesh, Gause, William, Salgame, Padmini
• Format: Article
• Language: English
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.190.Supp.187.18

Helminths are known to exert immunomodulatory effects on the host, an effect largely mediated by their induction of generalized Th2 responses. In a recent study, using the murine nematode Nippostrongylus brasiliensis (Nb), we have shown that a prior infection with Nb makes the host more susceptible to tuberculosis (TB). In this study we sought to investigate whether coinfection would exacerbate chronic infection, a phase where Mycobacterium tuberculosis (Mtb) is contained within granulomas. Mice chronically infected with Mtb were coinfected with Nb. We report herein that despite a helminth induced Th2 component, coinfected animals had a similar bacterial burden in comparison with Mtb alone infected animals. This observation could be due to the fact that the Mtb is already established in the granuloma and any effect of the helminth induced Th2 response is unable to shift this balance. In order to further understand the kinetics of helminths influencing TB, we infected mice with Mtb and these were infected 5days later with Nb. Interestingly we observed a significant increase in lung bacterial burden in coinfected animals. These results suggest that the timing of a helminth infection in an Mtb infected individual could have completely different outcomes. Studies are underway to unravel the mechanisms behind these observations. This finding is significant as a helminth infection can occur even during adulthood in endemic areas of the world, regions which are also endemic with TB